1. Field of the Invention
The present invention generally relates to a battery protection circuit and a battery protection method, and more particularly, to a battery protection method that can reduce the swelling of the battery under high temperature environment.
2. Description of Related Art
With development of technology in light, small and portable electronic products, various high performance components of the products are being developed with a trend toward being light, thin and small. As a result, batteries that are light-weighted and small-sized and have a large capacity are becoming particularly important. In addition to the small size and large capacity, a battery protection circuit designed to prolong the life of the battery and provide security to the user can be also rather important. Typical battery protection circuits only work for batteries which are being used, which provide monitor and protect during the charging and discharging states of the batteries. These protection circuits includes, for example, circuits for overcharge monitoring, over-discharge monitoring, excess current and short protection.
During the course of using the battery, overcharge may be caused by a user's misuse, which may raise the temperature of the battery and cause electrolyte of the battery to decompose to generate gas thus increasing an internal pressure of the battery. The overcharge may also cause leakage of the interior chemical solution which places the battery at a risk of catching fire. As a result, the overcharge monitoring protection circuit is used to detect if the battery is overcharged to avoid the deterioration of performance, catching fire, and breakage of the battery, thereby ensuring the user's safety during using the battery. The over-discharge monitoring protection circuit detects abnormity during the course of discharging to ensure the life of the battery. The excess current and short protection circuit is used to break the connection between the battery and a load in case of a current abnormity of the battery and enable the battery to return back to normal operation after the abnormity disappears, thereby protecting the battery.
Although these battery protection circuits can provide monitoring and protection to batteries that are being used, they cannot protect batteries that are not being used. For example, when a cell phone or a digital camera is placed in an internal space of a car that has a high temperature, although the battery inside the cell phone or the digital camera is not being used, abnormity or swelling of the battery may still occur due to the high temperature environment, which would reduce the life of the battery that is not being used and place the user in danger.